it was a lengthy , pains ##taking process , requiring thirty to fifty engraved printing blocks and up to seventy ink ##ings and impressions to create a single image . hu also employed a related form of multiple @ - @ block printing called " set @ - @ block printing " ( tao ##ban yin ##shu ##a , [UNK] [UNK] [UNK] [UNK] ) , which had existed since the yuan period some 200 years earlier but had only recently come into fashion again . he refined these block printing techniques by developing a process for wiping some of the ink off the blocks before printing ; this enabled him to achieve gr ##ada ##tion and modulation of shades which were not previously possible . in some images
it was a lengthy, painstaking process, requiring thirty to fifty engraved printing blocks and up to seventy inkings and impressions to create a single image. hu also employed a related form of multiple @ - @ block printing called " set @ - @ block printing " ( taoban yinshua, [UNK] [UNK] [UNK] [UNK] ), which had existed since the yuan period some 200 years earlier but had only recently come into fashion again. he refined these block printing techniques by developing a process for wiping some of the ink off the blocks before printing ; this enabled him to achieve gradation and modulation of shades which were not previously possible. in some images